diff --git a/core/src/main/java/com/google/zxing/oned/UPCEWriter.java b/core/src/main/java/com/google/zxing/oned/UPCEWriter.java
index 90d76c46ad..bb008c8adc 100644
--- a/core/src/main/java/com/google/zxing/oned/UPCEWriter.java
+++ b/core/src/main/java/com/google/zxing/oned/UPCEWriter.java
@@ -64,7 +64,7 @@ public boolean[] encode(String contents) {
         break;
       case 8:
         try {
-          if (!UPCEANReader.checkStandardUPCEANChecksum(contents)) {
+          if (!UPCEANReader.checkStandardUPCEANChecksum(UPCEReader.convertUPCEtoUPCA(contents))) {
             throw new IllegalArgumentException("Contents do not pass checksum");
           }
         } catch (FormatException ignored) {